The human visual system is a complex system with a great ability to absorb vast amounts of information originating in many varying formats, including visual displays. Visual displays are found in varying sizes and forms in today's world, displaying many types of information, from large visual display screens announcing scheduling information found in airports, to small visual displays, such as those incorporated into pocket calculators. Included within these visual displays are direct view displays, including projection displays, and virtual image displays. Of concern in the reduction in the size of visual displays, specifically those utilized in portable electronic devices, such as portable communications equipment, smart-card reader devices, or the like, is the display resolution quality and the maintenance of minimal power requirements and low manufacturing costs.
Of relevance in the reduction in size of visual displays, and the maintenance of resolution quality, is the human visual system's ability to process and integrate information, and the speed at which the visual system is able to do so. Accordingly, scanning techniques have become of great importance in the field of visual displays. In theory, the human visual system can process and interpret information no faster than approximately 60 Hz. Therefore, an image that is projected and scanned within 1/60th of a second to varying positions within a visual display is seen by the eyes of the viewer as one enlarged integrated image.
As an example, by moving an image of an "A" to six different locations within a visual display, at a speed of 60 Hz, the viewer will see one integrated image composed of six "A"s.
If the image is simultaneously content modulated, for example, the images are of six letters "A", "B", "C", "D", "E" and "F" that are individually and sequentially moved to six varying positions at a speed of 60 Hz., the viewer will see one integrated image composed of the six letters. This process, more commonly known as time-multiplexed imagery, can be utilized in the field of display technology through the use of scanners, and more specifically in the development of enhanced resolution miniature visual displays, including projection displays.
Scanning devices utilized today aid in increasing the resolution of visual displays and decreasing power requirements through the utilization of fewer light sources. These scanning devices can be found in many forms, most commonly electro-mechanical scanners incorporating mirrors, such as galvanometric scanners and polygonal scanners. Of particular interest, are virtual displays and projection displays and the use of mirrors to achieve scanning and thus generation of a displayed image. These types of electro-mechanical scanners are commonly quite large in size, therefore not amenable to the incorporation into a display device that is small, lightweight, operates with low power consumption and is meant to be portable in nature. In addition, mechanical scanners, are complex, require separate light sources and thus expensive to manufacture and in many instances utilize great amounts of power during operation.
Thus, there is a need for an electro-optical package for use in a miniature visual display that includes a small scanning device that allows for the generation of a high resolution miniature visual display, in particular either a virtual image display or a projection display. The package operates by employing a microscanner that utilizes "x" and "y" scanning techniques. In particular the microscanner operates by scanning individual lasers or laser arrays, to create a complete scanned image.
Accordingly, it is highly desirable to provide for an electro-optical package including a scanning device, that utilizes a silicon wafer having positioned on a cantilevered portion thereof, a single laser device or a plurality of laser devices, thereby providing for the scanning of an individual pixel, and/or pixels, and thus generating a low-powered virtual image display or a projection display for use with portable electronic equipment and an automatic focus mechanism for determination of focus distance from the laser diode light source.
It is a purpose of the present invention to provide a new and improved integrated electro-optical package including a laser diode microscanner and an automatic focus mechanism, including a photodetector, for use in virtual image display systems and projection display systems.
It is a further purpose of the present invention to provide a new and improved integrated electro-optical package including a laser diode microscanner which utilizes varying electrostatic charges to achieve "x" and/or "y" scanning, thereby allowing for the incorporation of the electro-optical package into miniature virtual image displays and projection displays.
It is a still further purpose of the present invention to provide for a new and improved integrated electro-optical package including a laser diode microscanner and an automatic focus mechanism, such as a detector, thus allowing for proper focusing of the image source relative to the display screen, etc.